(1) Field of the Invention
This invention relates to an expansive solidifying material which is used for improving the poor grounds. More particularly, the invention relates to an expansive solidifying material which contains the main components of gypsum, blast furnace slag and portland type cement and a hardening promoter of soluble aluminate.
(2) Description of the Prior Art
Generally speaking, the soils of alluvia and reclaimed lands are mainly composed of clay and silt and the water contents of the soils are large. Therefore, they are generally weak and, when such grounds are utilized, they must be stabilized by subjecting them to the improvement of soil.
In the conventional art, several kinds of lime type and portland cement type stabilizing materials have been employed for improving the properties of soils. However, various disadvantages are left unsolved, especially when the water content of the poor ground is high, a satisfactory stabilization of the ground cannot be expected.
With regard to the lime type stabilizing material, the quick lime generates heat during the use, which is undesirable in view of the safety in work. In addition, much dust is produced by the heat generation, which causes the environmental pollution to occur with a sanitary disadvantage. Further, in some cases, the slurry of milk-like solidifying material is poured into a poor ground and it is solidified by mixing with stirring. However, in such the method, any satisfactory result cannot be obtained in general cases.
Furthermore, the portland cement type stabilizing material is suitable for improving the surface soil which contains a relatively small quantity of water. However, it is not yet satisfactory for the fully poor ground.
In the case of sludge which contains difficult solidified organic materials, the hardening of the above mentioned stabilizing materials is retarded or the hardening becomes impossible. Furthermore, since the stabilizing material is generally used in a large quantity, it must be inexpensive. However, the prior art stabilizing materials are mostly expensive so that the use in a large quantity is economically disadvantageous.